Note: Descriptions are shown in the official language in which they were submitted.
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1
This invention relates to a process for incorpora-
ting a water-soluble active principle in a lipid and,
more particularly, for stabilizing a water-soluble
antioxidant in a lipidic phase.
The majority of oils and certain fats used in food,
cosmetic and pharmaceutical products are rich in poly-
unsaturated fatty acids and, because of this, are par-
ticularly sensitive to oxidation. Their stability can be
improved by the addition of synthetic antioxidants such
as, for example, BHA (butyl hydroxyanisole), BHT (butyl
hydroxytoluene) or TBHQ (tert.butyl hydroquinone).
Unfortunately, the harmlessness of these compounds is
questionable.
Attempts have been made to replace them with natural
antioxidant compounds of the fat-soluble type such as,
for example, the tocopherols or ascorbyl palmitate or of
the water-soluble type such as, for example, ascorbic
acid, vegetable extracts, organic acids or amino acids.
In the case of the water-soluble compounds, an emulsi
fier, such as a phospholipid for example, has to be used
for incorporating the water-soluble antioxidants in the
oils in the form of micelles.
By virtue of their structure, the phospholipids are
capable of creating associations with certain water
soluble compounds to form micelles which, for their part,
are fat-soluble.
The incorporation of vitamin C or other water-
soluble compounds in oils using phospholipids is known,
for example, from EP-A-0 326 829. Unfortunately, this
known process uses an organic solvent, for example
ethanol, which promotes the formation of a single phase
in view of its hydrophilic and lipophilic properties. In
addition, the process in question - which uses an unfrac-
CA 02150399 2002-08-07
2
tionated Soya lecithin - is attended by the disadvantage that
problems of colour, odour and flocculation in storage cannot
be avoided.
According to U8-A-5,084,289, inverse micelles, i.e.
micelles in which the continuous phase is the lipophilic phase,
are formed by dissolving in an oil a phospholipid and then a
small quantity of an aqueous solution containing a water
soluble antioxidant, for example vitamin C, in a high
concentration. The mixture is stirred to form inverse micelles,
a single phase thus being obtained. The small quantity of
aqueous phase relative to the lipidic phase makes
homogenization difficult or even virtually impossible on a
large scale. In addition, it is only possible by this process
to incorporate substances highly soluble irx wager, for example
vitamin C, and not sparingly water-soluble substances such as,
for example, ethylene dinitrogetraacetic acid (EDTA). Finally,
this process does not avoid the appearance of undesirable
colours and odours in storage because the lecithin is not
fractionated.
It has now surprisingly been found that these disadvantages
can be completely eliminated by using a lecithin fraction
substantially free from phosphatidyl choline.
According to one aspect: o.f the present invention there is
provided a process for incorporating a water-soluble active
principle in a fat in the presence of lecithin, characterized
in that the lecithin is treated to produce a lecithin fraction
substantially free from phosphatidyl choline, an aqueous
solution of the water-soluble active principle is incorporated
in the mixture of this fraction and fat in liquid form with
vigorous stirring in a quantity sufficient to hydrate the
lecithin fraction to farm a heterogeneous mixture and the
mixture obtained is dried and thus become homogenous.
According to a further aspect of the present invention
there is provided a process for incorporating a water-soluble
active principle in a fat which comprises treating lecithin to
produce a lecithin fraction which is substantially free from
phosphatidyl choline, forming a mixture of the lecithin
CA 02150399 2002-08-07
2a
fraction and liquid fat, adding a water soluble active
principle, with vigorous stirring, in an amount sufficient to
hydrate the lecithin fraction and form a heterageneous mixture
and drying the heterogeneous mixture to form a homogeneous
composition.
According to another aspect of the present invention there
is provided a process for incorporating a water--soluble active
principle in a fat which comprises treating phospholipids to
produce a phospholipid fraction which is substantially free
from phosphatidyl choline, forming a mixture of the
phospholipid fraction and liquid fat, adding a water soluble
active principle to a quantity of water with agitation for a
sufficient period of time of_ about 10 to 30 minutes at a
temperature of about 60°C. to about 80°C. and under an
atmosphere sufficient to incorporate th.e water-soluble active
principle into the water, adding a sufficient amount of the
water to hydrate the phospholipid fraction to hydrate it and
form a heterogeneous mixture, and drying the heterogeneous
mixture to form a homogeneous composition.
According to a still further aspect of the present
invention there is provided a food, cosmetic or pharmaceutical
product containing a homogeneous composition prepared by a
process as defined above.
3
In the context of the present invention, a "lecithin
fraction substantially free from phosphatidyl choline" is
understood to be a fraction obtained from commercial
lecithin, for example Soya, by a treatment which enables
the phosphatidyl choline to be separated from the other
constituents, such as phosphatidyl ethanolamine, phospha-
tidyl inositol and phosphatidic acid, hereinafter refer-
red to as "other PLS" (other phospholipids).
In a first embodiment, the commercial lecithin is
treated in solution in the oil with a bleaching earth as
adsorbent, after which the oil thus treated is separated.
In a second embodiment, which is preferred, the
lecithin is treated in solution in a mixture of organic
solvents by liquid chromatography in a column of silica
gel in known manner and the fraction containing the other
PLS, which is also freed from most of the triglycerides,
is collected.
The water-soluble active principles envisaged in
accordance with the invention are, for example, cosmetic
or dermatological agents or water-soluble antioxidants.
They include, for example, conventional antioxidants, for
example vitamin C, vegetable extracts, for example
rosemary, green tea, organic acids, for example hydroxy
acids, such as citric acid, phenolic acids, for example
caffeic, quinic and chlorogenic acids, caffeine, amino
acids, phenyl indanes and sequestering agents, for
example citrates or EDTA.
The fat to be protected against oxidation is rich in
unsaturated fatty acids, more particularly polyunsatura
ted fatty acids. The fat may be a vegetable oil, for
example sunflower oil, wheat germ oil, grapeseed oil,
corn oil, safflower oil, olive oil, evening primrose oil,
borage oil and blackcurrant seed oil, or an animal oil,
for example chicken fat, butter oil, a marine animal oil,
more particularly fish oil.
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4
The incorporation of the water-soluble active
principle takes place with vigorous stirring at a temper-
ature above 60°C and preferably at a temperature of the
order of 80°C. The water-soluble active principle may be
introduced in the form of an aqueous solution or, alter-
natively, in dry form, in which case water is subsequent-
ly added. The quantity of water in the mixture should be
sufficient to hydrate the quantity of lecithin fraction
which it contains. It represents 2 to 8% by weight of
the mixture and, preferably, approximately 5% thereof.
This operation takes place over a period of 10 to 30
minutes in the absence of air, for example in a nitrogen
atmosphere, which results in the formation of a hetero-
geneous mixture.
The water is then eliminated from the heterogeneous
mixture by heating in vacuo, preferably to 60 to 90°C and
advantageously to 60 to 70°C under a vacuum of 0.5 to 35
mbar. A homogeneous and stable micellar phase is formed.
The invention is illustrated by the following
Examples in which parts and percentages are by weight,
unless otherwise indicated.
Example 1
A refined Soya lecithin low in heavy metals (Top
cithin 200~) and containing 60% of phospholipids (refer
red to hereinafter as PLS) is dissolved under nitrogen
in a sunflower oil (SFO).
The solution is then treated with a bleaching earth
(Tonsil Optimum FF~) for 30 minutes at 85 to 90°C, under
a pressure of 35 mbar and in the presence of a foam
inhibitor (Rhodosil 70414~), the quantity of adsorbent
corresponding to four times the quantity of phospho-
lipids, after which the solution is separated from the
adsorbent by filtration.
The quantities shown in Table 1 below of vitamin C
~~ ~~39~
and EDTA in solid form and then 5% of demineralized water
are subsequently added to the solution. After vigorous
stirring under nitrogen for 15 minutes at 80°C, a hetero-
geneous mixture is obtained and is then dried for 30
minutes at 80-90°C under a pressure of 35 mbar and then
0.5 mbar and filtered. A homogeneous micellar phase is
obtained.
The stabilized oil (1a) is evaluated by comparison
with the same, unstabilized oil (lb) and with an oil
stabilized with a commercial lecithin which has not been
treated with bleaching earth (1c):
- From the point of view of their stability to oxidation
as measured by the Rancimat~ accelerated oxidation test
at 110°C. The induction times obtained, expressed in h,
represent the OSI (oil stability index) values.
- From the point of view of their stability in storage at
15°C by visual and olfactory assessment.
The results obtained are set out in Table 1 below:
Table 1
Test PL Vit. EDTA Treat- OSI, Colour
C
mg/kg mg/kg mg/kg ment 110C,h
1a 10000 1000 200 Yes 19.5 Yellow
lb ---- ---- ---- ---- 5 Light
yellow
1c 10000 1000 200 No 17.5 Orange-
yellow
It can be seen that the treatment of lecithin with
a bleaching earth improves its colour and increases its
stability to oxidation.
Examples 2-10
SFO is stabilized in the same way as in Example 1
using vitamin C in conjunction with various sequestering
agents in various quantities. The OSI values of unstabi-
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6
lized SFO (2a) and SFO containing the PL fraction treated
with the adsorbent (2b) are measured by way of compari-
son.
The protection factor (PF), which corresponds to the
quotient:
PF = OSI of the stabilized oil/OSI of the unstabilized
oil (this quotient represents the increase in the induc-
tion time),
is calculated from the OSI values.
The results are set out in Table 2 below:
Table 2
Exam- PL Vit.C Segues- SA OSI PF Stability
ple mg/kg mg/kg tram, mg/kg 110C, at 15C
SA h after 5d
2a ---- ---- ---- ---- 5 1 Clear
2b 5000 ---- ---- ---- 5.7 1.14 Clear
2 5000 1000 ---- ---- 19 3.8 Slightly
cloudy
3 5000 1000 EDTA 100 22.5 4.5 Slightly
cloudy
4 5000 1000 EDTA 200 22 4.4 Clear
5000 1000 EDTA 400 20 4 Clear
6 5000 1000 EDTA 200 21 4.2 Slightly
Na2 cloudy
7 5000 1000 Citric 200 17 3.4 Slightly
acid cloudy
8 5000 1000 Citric 200 20.5 4.1 Slightly
acid cloudy
Na3
9 5000 1000 Citric 400 16 3.2 Clear
acid
Na3
5000 1000 EDTA 200 21.8 4.36 Slightly
citric cloudy
acid
Na3
~~ ~fl39a
7
It can be seen that the use of PL on its own is not
sufficient to stabilize the oil (2b compared with 2a).
Examples 11-15
Following the procedure of Example 1, SFO stabilized
with various ratios of vit.C to PL is evaluated for
stability in storage, OSI and PF. The results are set
out in Table 3 below by comparison with the unprotected
oil (lla) and with the same oil to which 1.66% of a
ternary mixture of vit.C, PL and vit.E in quantities of
1000 mg/kg vit.C, 4500 mg/kg PL and 500 mg/kg vit.E is
added (llb).
Table 3
Exam-PL Vit.C EDTA Vit.C/ OSI PF Stability
ple mg/kg mg/kg mg/kg PLx100 110C, at 15C
h after 5d
lla ---- ---- ---- ---- 5 1 Clear
llb 4500 1000 ---- 22 15.8 3.16 Slightly
+500 cloudy
mg/kg
vit.E
11 2500 1000 200 40 14.7 2.94 S1lght1y
cloudy
12 5000 1000 200 20 22 4.4 Slightly
cloudy
13 6600 1000 200 15 20.8 4.16 Slightly
cloudy
14 7500 1000 200 13.3 20 4 Clear
15 10000 1000 200 10 20 4 Clear
It can be seen that the use of a ternary mixture
comprising vit.E does not improve the stability of the
oil or its antioxidant properties in relation to the use
of a mixture of PL and vit.C (11b compared with 11-15).
Accordingly, it may be concluded that the synergism
between vit.C and vit.E already occurs with the vit.E
8
naturally present in SFO (corresponding to 760 mg/kg).
Accordingly, for vegetable oils naturally containing
vit.E, the addition of more vit.E is not beneficial.
The stabilized oils were stored for 1 month at 15°C.
It was found that the oils stabilized with a ratio of
vit.C to PL of greater than 13% became cloudy during that
period. Accordingly, this ratio is preferably less than
or equal to 13% to ensure optimal stability of the oil.
Examples 16-19
Following the procedure of Example 1, SFO stabilized
with various quantities of vit.C (the ratio of vit.C to
PL being constant) was evaluated for stability in stor-
age, OSI and PF. The results obtained are set out in
Table 4 below by comparison with the unprotected oil
(16a).
Table 4
Exam-PL Vit.C EDTA Vit.C/ OSI PF Stability
ple mg/kg mg/kg mg/kg PLx100 110C, at 15C
h after 30d
16a ---- ---- ---- ---- 5 1 Clear
16 2500 250 200 10 12.3 2.4 Clear
17 5000 500 200 10 16 3.2 Clear
18 7500 750 200 10 18 3.6 Clear
19 10000 1000 200 10 20 4 Clear
Examples 20-24
Following the procedure of Example 1 to stabilize
blackcurrant seed oil (BCSO), BCSO stabilized with a
constant ratio of vit.C to PL is evaluated for stability
in storage, OSI and PF. The results are set out in Table
below by comparison with the unprotected oil (20a) and
with the same oil to which 1.66% of a ternary mixture of
vit.C, PL and vit.E in quantities of 1000 mg/kg vit.C,
4500 mg/kg PL and 500 mg/kg vit.E (20b) has been added.
9
Table 5
Exam-PL Vit.C EDTA Vit.E Vit.C/ OSI PF Stability
ple mg/kg mg/kg mg/kg mg/kg PL x 100C, at 15C
100 h after 20d
20a ---- ---- ---- ---- ---- 4 1 Clear
20b 4500 1000 ---- 500 22 17.5 4.38 Slightly
cloudy
20 10000 1000 ---- ---- 10 19.8 4.95 Clear
21 10000 1000 ---- 500 10 17.6 4.4 Clear
22 10000 1000 400 ---- 10 24 6 Clear
23 10000 1000 400 500 10 20.2 5.05 Clear
24 5000 500 200 ---- 10 17.2 4.3 Clear
The results confirm those obtained with SFO (Ex-
amples 11 to 15), namely that the addition of vit.E does
not improve the stability of BCSO to oxidation but would
actually seem to have a pro-oxidizing effect in a vege-
table oil naturally containing around 750 ppm of vit.E
(Example 22 compared with 23).
Example 25
Following the procedure of Example 1 to stabilize
chicken fat free from vit. E, the chicken fat is evaluated
for OSI, PF and colour with and without added vit.E by
comparison with the unprotected fat. The results ob-
tained are set out in Table 6 below.
Table 6
PL Vit.C Vit.E EDTA OSI PF Colour after
mg/kg mg/kg mg/kg mg/kg 120C,h Rancimat
---- ---- ---- ---- 2 1 Yellow
5000 500 ---- ---- 7.3 3.65 Yellow
5000 500 250 ---- 16.5 8.25 Orange
5000 500 ---- 100 10.5 5.25 Yellow
5000 500 250 100 19.3 9.65 Yellow
~~~o~oo
The above results confirm that the synergistic effect
between vit.C and vit.E exists when the fat to. be pro-
tected does not naturally contain vit.E.
Example 26
A soya lecithin free from PC (other PLS fraction),
which has been obtained as second fraction by liquid
chromatography in a column of silica gel using a mixture of
hexane, 2-propanol and water in a ratio of 1:1:0.1, is
dissolved in SFO. A first fraction rich in phosphatidyl
choline (PC fraction) is also collected.
Quantities of 10,000 mg/kg of each lecithin fraction,
1000 mg/kg of vit.C and 200 mg/kg of EDTA in solid form and
then 5% of demineralized water are added to the oil. After
vigorous stirring under nitrogen for 15 minutes at 20°C, a
heterogeneous mixture is obtained and is dried for 30
minutes at 80 to 90°C under a pressure of 35 mbar and then
0.5 mbar. Filtration gives a homogeneous micellar phase in
the case of the oil stabilized with the other PLS fraction.
By contrast, the PC fraction could not be dissolved in oil.
The OSI is then evaluated. The results are set out in
Table 7 below.
Table 7
Phospholipids OSI 110°C Remarks
PC Fraction ---- The fraction could not
be dissolved in the oil
Other PLS fraction 21 The fraction dissolves
in the oil which is
perfectly clear
Examples 27-31
SFO is stabilized with various water-soluble
antioxidant active principles in the same way as de-
scribed in Example 26. The results are set out in Table
8 below. SFO with no additive (27a) was evaluated for
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11
comparison.
The phenyl indanes were obtained from coffee by the
extraction process according to European Patent Application
No.94109355.1 filed on 17.06.1994 under the title "Phenyl
indanes, a process for their production and their uses".
Table 8
Example PL Active AP EDTA OSI PF
mg/kg principle mg/kg mg/kg 110C,h
(AP)
27a ____ -___ ____ ____ 5 1
27 10000 L-histidine 1000 200 11.5 2.3
28 10000 L-cysteine 1000 200 12 2.4
29 10000 Rosemary 1000 200 14 28
extract
30 10000 Green tea 1000 200 12 2.4
extract
31 10000 phenyl 500 ---- 30.5 6.1
indanes
Examples 32-33
The procedure described in Example 1 up to hydration
of the PLS is used to stabilize an SFO. The drying step
is carried out at various temperatures. The antioxidant
properties and the colour of the stabilized oils are
evaluated by comparison with the unstabilized oil (32a).
The results are set out in Table 9 below.
___ __~3
. _
12
Table 9
Exam- Drying PL Vit.C EDTA OSI PF Colour
ple temper- without mg/kg mg/kg 110C, measurement
ature PC h Lovibond
5.25"
Y R
32a ---- ---- ---- ---- 5 1 8.4 1.3
32 80- 10000 1000 400 21 4.2 43 4.8
90C
33 60- 10000 1000 400 22.8 4.56 18.5 2.7
70C
It can be seen that the colour is less intense where
drying is carried out at a lower temperature.
